This invention relates to the treatment of gases produced in coal conversion processes, such as coke-oven gases.
Coke-oven gases produced, for example, from the operation of a battery of coke ovens contain, in addition to the major constituents of H.sub.2, CH.sub.4, CO and CO.sub.2, a number of other substances such as unsaturated hydrocarbons, NH.sub.3, HCN, benzene and other aromatic hydrocarbons, as well as tar, H.sub.2 S, and organic sulphur compounds. To use these gases further, it is necessary to remove a substantial amount of these accompanying substances. To this end, hot coke-oven gases have heretofore been cooled in a subsequent condensation stage. Using an auxiliary reclamation process, napthalene, NH.sub.3, benzene, tar and sulphur have been separated and reclaimed, for example. The market value of such by-products, however, is low; and, therefore, the by-products cannot be reclaimed economically. Nevertheless, because of the undesirable nature of these substances in the raw gas, they must be removed before the gases can be released to the environment. Frequently, the purification process itself generates environmentally harmful waste water and gases, which must be eliminated at great expense.
In an attempt to avoid these disadvantages, it has been suggested that the raw gases from the coke-oven while still hot, i.e., without cooling and purification, be subjected to partial oxidation with the aid of oxygen, oxygen-enriched air, or other oxygenic gas mixtures to thereby convert the undesirable constituents thereof to a carbon monoxide and hydrogen-rich separated gas stream. However, these processes require considerable amounts of oxygen and thus require an oxygen supply at additional capital investment or at considerable cost.